<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"/>
        <title>Varijable</title>
    </head>
    <body>
    <script type="text/javascript">
    var broj = 4e5;
    var heder ="<header> Ispis teksta u heder tag</header>";
    document.writeln("broj " + broj);
    //alert(broj);  
    document.write(heder);
    </script>
    </body>
</html>